A collection of reagents and other associated materials intended to be used for the quantitative measurement of multiple blood gas, haemoximetry and/or electrolyte analytes in a clinical sample, using multiple technologies such as ion-selective electrode (ISE) and haemoximetry in a single analyser. Analytes detected may include partial pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), pH, sodium, potassium, ionized calcium, chloride, glucose, lactate, total haemoglobin (totHb), haematocrit, and haemoglobin derivatives such as reduced haemoglobin (RHb), methaemoglobin (MetHb), sulfhaemoglobin (SHb).